Had it just been this one Apple purchase or a Facebook visit then I'd agree, there's always something you'll miss and it's much easier to point this out afterwards. But it appears that he didn't use a single method to hide his identity.
On the other hand, perhaps he thought that living in the Ukraine would give him enough protection against US agents.
The hindsight bias is realizing how serious the situation might be and the level of OPSEC that is required. When the torrent site was first created the risk level wasn't known and most people didn't understand how hard it is to avoid the ubiquitous sensors of the surveillance-industriual-complex. Yes, more people probably should have assumed this level of risk much earlier, but that's easy to say now when we know names like Prism and XKEYSCORE.
[1] (note: contains rude/strong language) https://www.youtube.com/watch?v=J1q4Ir2J8P8